Stanley Proto J7218HF 3/8-Inch Drive High Strength Magnetic Impact Socket, 9/16-Inch, 6 Point ProtoGrip Magnetic Sockets use high strength magnets made from a rare earth magnet alloy/nylon blend ProtoGrip Magnetic Sockets require no bushings to hold the magnet in place Designed to easily pick up heavy fasteners and hold them tightly during use Strong magnetic hold helps increase efficiency when installing fasteners in awkward or hard-to-reach locations Impact sockets with high impact strength are used in automated and hand impact socket applications